As President Donald Trump continues his cyberbulling campaign against Attorney General Jeff Sessions, the Department of Justice has identified a Paul Manafort business associate as a top Russian mob boss.

Dmytro Firtash – a Ukrainian oligarch and Vladimer Putin supporter with close ties to Paul Manafort – was accused of being in an “upper-echelon [associate] of Russian organized crime,” NBC News reports.

This could be a significant development as Special Counsel Robert Mueller seeks leverage over Manafort and federal investigators seek to get Manafort to “flip” and testify against President Trump.

After Firtash’s attorney’s tried to get bribery charges dismissed, the government responded with a 115-page filing against the Ukrainian oligarch with close ties to Russian President Vladimer Putin.

Previously, Firtash has admitted to his involvement with the Russian mob.

“Also in 2008, according to a State Department cable posted by WikiLeaks, Firtash told U.S. Ambassador William Taylor that he got his start in business with the permission of one of Russia’s most well-known organized crime bosses, Semion Mogilevich,” NBC News reminded.

Firtish transferred $25 million into an escrow account to fund a business venture with Manafort to buy the Drake Hotel for $850 million. The Drake deal was named in a 2014 racketeering lawsuit, which was later dismissed.

The relationship between Firtash and Manafort was as political as it was financial. Manafort worked for Ukraine’s Party of Regions and Firtash was a major backer of the party.

NBC reported that, “Another leaked cable said that Manafort’s job in 2006 was to give the Party of Regions an ‘extreme makeover’ and ‘change its image from … a haven for mobsters into that of a legitimate political party.'”